Sculpting material and method of manufacture and use

ABSTRACT

A dry, three-dimensional, sculptable solid comprising a quantity of granular material comprising grains individually coated with paint and a water resistant binder binding the grains of the granular material together into a solid, dry, carvable block having a hardness between about 0.25 and about 4.0 on the Moh&#39;s scale.

BACKGROUND OF THE INVENTION Field of the Invention

This invention relates to artificial sculpting material and to theproduction and use of such material.

Education, especially in elementary forms, is undertaken not so much tomake the student an expert in the field as to give the studentsufficient proficiency to understand the use of the technique, whetherin the so-called useful arts of arithmetic, writing, manual training,physical training, and others, or in the arts of painting, sculpture,poetry, dance, and others, which are sometimes referred to asdecorative, or fine, arts. Among the fine arts, two-dimensional graphicexpression has been assisted by the availability of a wide variety ofmaterials suitable for use by students of every age and level ofexpertise. Sculpture, in contrast, has not been so fortunate. Clay, fromwhich three-dimensional forms can be produced, is relatively easilyprocured by students at all levels, but solid stone in a form that canbe carved by even the youngest students is not. Clay allows thecorrection of mistakes and changing of thought, since clay sculpturesare produced by adding soft clay to whatever is already there. Stone,which is carved only by removal of material that, once gone, cannot bereplaced, cannot be corrected nearly as easily. There is a discipline instone unmatched by the rectifiable modeling permitted by clay. However,clay is much used by modern sculptors, even those of great artisticability, who employ assistants who are less creative but aresufficiently manually proficient to produce a final work of art in stoneaccording to the clay prototype created by the artist. It has been saidthat it may be this very lack of experience in working with stone thatmakes it difficult for the modern sculptor to become a thorough masterof the art, thinking naturally in stone rather than in clay.

A characteristic of a stone sculpture, equal in importance to thedisciplines of forethought and accuracy imposed on the sculptor, is thepermanence of the finished work of art. No gentle force, whether ofimpact, wind, or water, should be able to make an easily observableeffect upon it in a measureable span of time.

The Prior Art

Stones have been synthesized for many purposes, one common one being foruse as grinding stones, as described in U.S. Pat. No. 3,661,544 toWhitaker; U.S. Pat. No. 3,864,101 to Charvat; U.S. Pat. No. 4,035,162 toBrothers et al.; and U.S. Pat. No. 4,350,497 to Ogman. Other forms ofabrasive material are described in U.S. Pat. No. 4,078,340 to Klecker etal. and U.S. Pat. No. 4,221,572 to Torimae et al. In none of these isthe final material intended to be sculpted into some desired shape.Quite the contrary, grinding stones do the shaping of other material,and it is the essence of grinding stones to hold together while removingmaterial from work pieces.

Another prior material synthesized from sand and resin is that used inmolds in which molten metal is cast. In such materials, the resin isused to held the grains of sand together securely enough to allowcomplex molds to be formed, which can be used directly in castingcomplex metal pieces that require less machining to finish than would berequired if the machining had to be done on more crudely cast shapes.However, the molds formed for casting are intended to be broken up asthe cast piece is removed from the mold after it has solidified. Thereis never any intention that the mixture of resin and sand be sculptedbeyond very minor touching up of the mold to correct small inaccuracies,such as visible parting lines and the like. In particular, there is noneed to color the sand, either in a single color or in intermingledcolors, nor to make it attractive for its own sake as a work of art; itis completely utilitarian.

SUMMARY OF THE INVENTION

In accordance with the present invention, sculpting material is producedby mixing granular material with a suitable paint to color theindividual grains. The grains thus colored are dried and eithermaintained in or returned to granular form. In some cases, the processmay be repeated one or more times to increase the intensity of thecolor. The granular material is dried after each application of a layerof paint, and the dried, colored granular material can be stored forfuture use, or it can be used immediately to form a sculpting stone orstones.

The formulation of sculpting stones from the colored granular materialis accomplished by adding binding materials similar to those used in themetal casting industry to form foundry molds. However, the configurationof sculpting stone and certain criteria of its final use dictatelimitations that are not relevant to the metal casting industry. For onething, the essence of stone intended to be used for sculpting is that itbe carvable so the pieces of controllable size, down to the most minute,can be removed from an initial block at the will of the sculptor; itwould be most undesirable to have large chunks break off when thesculptor only wanted to remove a tiny bit. Foundry molds for metalcasting are not sculpted but are used in the shape in which they aremolded. Thus, it is not necessary that they be carvable. After meal hasbeen cast in and around them, they are broken down into the granularstate from which they started.

For another thing, foundry molds are not expected to last long. Thecasting process is carried out right away. Thus, in the case of suchmolds, solubility in water may even be helpful, or at least not harmful,in removing the binding material. In sculpting stone, on the contrary,it is important that the binding material not be affected by water,because that would make the sculpture susceptible to being defaced andeven eroded back to its original granular state. Sculptures of suchmaterial would be not be enduring, as stone sculptures are expected tobe.

In addition, some binding materials used in foundry mold-making have amost unpleasant odor. This can be dealt with by the powerful ventilationsystem in a foundry, but working closely on a malodorous sculpting stoneto shape it precisely in a moderately ventilated classroom or art studiois unpleasant. Thus, the binding material must be resistant to water andmust not have a bad odor.

I have found that alkyd resins, such as the 18-00 series produced byDelta Resins & Refractories, Inc., of Milwaukee, Wisconsin, are quitesuitable. I mix the resin with the previously colored granular materialto form a slurry with which I then mix a suitable coreactant, such asDelta's 23-217 coreactant. The time within which the materials can bestirred together before they begin to set is determined by the catalystused and the amount of the catalyst. Delta produces a catalystidentified at their 1718-X catalyst, which may be mixed with the resin,initially, or may be sold separately to be added later. Adding thecatalyst later allows the drying time of the mixture to be controlledaccording to the nature of the sculpting stone being produced. Dependingon the desired end product, I may pour it into one or more molds tosolidify. If the product is one that is formed as a relatively largelayer, it may be left to dry in the container in which it is mixed.After the slurry has been poured into molds, if that is to be done, themolds are vibrated to release air bubbles and settle the mixture. If theslurry is not poured out of the mixing container, that container isvibrated. The slurry is then allowed to solidify, after which it may becut into pieces ready to be sculpted.

The invention will be described hereinafter in conjunction with theaccompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a block of sculpting stone according to this invention.

FIG. 2 shows a marbleized form of sculpting stone according to thisinvention.

FIG. 3 shows yet another form of sculpting stone made according to thisinvention and partially carved into an abstract work of art.

FIG. 4 shows a partially sculpted block in which a finished form isencased, in accordance with this invention.

FIG. 5 shows a sculpting stone of random shape containing othersculpting stone solids and other materials according to this invention.

DETAILED DESCRIPTION OF THE INVENTION

A block of sculpting stone II in FIG. 1 is formed principally of agranular material, such as sand, although other granular materials maybe used instead. The fineness of the grains determines how smooth thesurface of a sculpture made from the stone II can be. The higher thegrain fineness number (sometimes simply stated as GFN), the smaller thegrains and, therefore, the smoother the surface. The grain finenessnumber is the approximate number of mesh openings per inch of a sievethat would just pass a sample of granular material if the grains in thesample were of uniform size. The American Society for Testing Materials(A.S.T.M.) has established mesh numbers from 3.5, corresponding to sieveaperture diameters of 7.93 mm, to 400, corresponding to sieve aperturediameters of 0.037 mm. Thus, numerically the mesh numbers are inverselyproportional to the size of the largest grain that can pass throughthem. While granular material having large grains that will only passthrough sieves with mesh numbers of 6 or below can be used to makesculpting stones, especially for large sculptures to be mountedoutdoors, I have found that smaller grain sizes are more universallysatisfactory, such as grains that will pass through sieves having meshnumber in the range from about 40 to 180. Preferably the granularmaterial corresponds to mesh numbers in the range from about 100 to 140,with a mesh number close to 120 being the optimum size.

It is well known to select sculpting material, such as marble, accordingto its color, but the range of colors is somewhat limited. Thisinvention, on the other hand, makes it possible to obtain sculptingmaterial that has any one or more of a wide variety of colors. Suchcoloring extends relatively uniformly through the entire sculpting stoneand is achieved by applying paint to the granular material beforeforming it into a block. The paint I have found to be most satisfactoryis an oil-based alkyd, but other paints, such as latex, acrylic lacquer,acrylic enamel, acrylic urethane, polyurethane enamel, epoxy marinepaint, and others may be used instead. In the case of alkyd paint, anamount between about 1/4 lb. and 5 lbs. should be mixed with each 100lbs. of sand, although the ratio is preferably not more than about 21/2lbs. of alkyd paint to 100 lbs. of sand. The finer the grains of sand,the larger the surface area of a given weight of and, and, thus, thelarger the quantity of paint required within the foregoing ratio. If itis not known that the grains of sand are of the proper size, the sandshould be screened before the paint is added to it, partly to provideuniformity of the end product and partly to determine the amount ofpaint to use.

After mixing the paint and sand together, the painted sand should bespread out to dry. It is important that the painted sand not only be drybut be in particulate form before it is used in the next step of theprocess, and, accordingly, I have found it desirable to rescreen thedried material through a sieve of the same number as the firstscreening. The material may have to be broken up to return it toparticulate form before rescreening it. Due to the increase in diameterof the grains because of the paint on them, about two or three percentof the grains will be lost in the rescreening. If a more intense coloris desired, the painted grains may be mixed with more paint, dried, andrescreened. The process can be repeated again, although one or tworepetitions should usually be enough. The painted, dry sand can bestored in a closed container or used without delay in forming sculptingstone in accordance with the rest of the procedure, as describedhereinafter.

The block 11 shown in FIG. 1 may be considered typical of my sculptingstone. In this embodiment it has three layers of different colors, butthis is only one of a virtually infinite number of arrangements of thematerial. The color is uniform throughout each layer since there is alayer of paint on virtually every grain, and any article sculpted fromblock 11 will display the bands of colors of the layers 12-14 across thecarved surfaces. The resulting article will have an added quality ofinterest over the same article made of monochromatic sand, and mayparticularly intrigue new students of the art, although monochromaticpainted said is perfectly satisfactory for many sculptures and would beless expensive. The multi-colored sand, though, is likely to lead to thedesired result of stimulating new students particularly young ones, towork harder.

The layers 12-14 in this embodiment can be made to differ only in colorwhile remaining of equal hardness to each other. Thus, the sculptor,whether experienced or not, will not be forced to use different tools onparts of the sculpture that fall in different layers, nor will there beany need to apply different pressure to the tools in going from layer tolayer. Uniformity of carvability is usually a desirable characteristic,although there may be occasions when the layers should be formed so thatthey will have different hardnesses, as will be described hereinafter.

The grains in each of the layers, e.g., layer 12, are bound together bya matrix of a suitable resin with which the painted granular material ismixed. The mixture is initially a slurry, which hardens into a solidlayer in due time according to the hardening, or catalytic drying, agentused.

The layer may be anywhere from a fraction of an inch to many inchesthick, and its width and length may also vary from less than an inch tomany inches. Depending on the expected end use of the layer, after ithardens, it may be removed from the container in which it is formed andcut into smaller pieces before being turned over to a sculptor, or itmay be left as one piece. If it is to be combined with other layers 13and 14, its surface 16 may be smoothed into a flat plane, or the firstlayer may be left in its as-formed state, and the second layer may beformed by pouring a second slurry directly on its exposed surface 16.The layer 14 may be formed in the same way on the surface 17 of thelayer 13, or it may be formed as an entirely spearate, solid layer. Inthe latter case, the solid layers 12 and 14 may be supported with theirsurfaces 16 and 18 suitably spaced apart and juxtaposed to each other,and the slurry that will form the layer 13 poured between them. In anycase, the layers 12-14 may be made of identical constituents (except forthe color of the paint) so that the final block 11 will have uniformsculpting qualities throughout, unlike some natural materials.Furthermore, the resin in the slurry at each interface between thelayers bonds them to each other to form a single block 11 that holdstogether uniformly. This is another respect in which the artificialsculpting stone of this invention differs from, and is an improvementover, some natural materials that have weak internal surfaces that maycrack, even after much work has been done on them by the sculptor.

Permanence, at least in the absence of deliberate destruction, is one ofthe most desired characteristic of a sculpture, whether it be made by aprofessional artist or a child just learning the techniques. The mostlikely source of insidious destruction of a sculpture carved of any formof stone is the atmosphere, or, more properly, some of the components inthe atmosphere. The component likely to do the greatest damage in theshortest time is water vapor, even in the case of a sculpture keptindoors. Consequently, it is desirable to use materials that are asinsoluble in water as possible, provided, of course, that they areotherwise satisfactory. I have found that an alkyd binder resin sold byDelta Resins & Refractories, Inc., as their 18-00 and 18-001 seriesworks very well. Such material is intended to be added to sand to formmolds (and cores) for use in casting metal. The resin is a liquid and,when mixed with sand, forms a slurry that is then poured into a mastermold. There the slurry hardens so that the mold thus formed will notcrumble when, or before, molten metal is poured on or into it. However,such molds are not permanent articles. They are intended to be used onlyonce and are likely to be broken, frequently deliberately, in separatingthem from the solidified metal or, if not then, shortly afterward, sothat the sand in them can be used to form a new mold.

Along with the alkyd resin, foundries use Delta's coreactant 23-217 toharden the resin. the coreactant contributes to the polymerization ofthe resin, and the degree of hardness can be controlled. In the case ofthe block 11, such control of hardness may be used to make one or moreof the layers 12-14 harder than the other layer or layers or to make thewhole block 11 harder or softer, by controlling the amount of coreactantused in every layer. The amount of resin used is about 0.25% to about 5%of the weight of the sand, depending on the type of sand, the grainsize, and the amount and type of paint used. The alkyd paid takes theplace of some of the alkyd resin that would otherwise be required,partly by filling up some of the interstices in the grains and leavingless space to be filled up by the resin. The amount of the coreactant isabout 15% to about 22% of the amount, by weight, of the resin.

The hardness of a compound material, such as the material beingdescribed, in which the grains, if of sand, are extremely hard and theresinous matrix material is much more frangible, cannot be easily placedon the Mohs scale. However, it is desirable that the block 11 be easy tocarve, especially if it is to be used by a child. In comparison tonatural materials, the sculpting stone, as a whole, should be less thanabout 4.0 on the Mohs scale and preferably less than about 2.0. At thesoftest, it may be desirable that it be carvable by a stiff-bristledbrush, which would place the lower limit at about 0.25 on the Mohsscale.

A further characteristic of this material is that the smallest incrementremoved in carving it be approximately one grain, and that the materialnot be separated in flakes or by spalling. It should not have anystickiness resembling tar.

The coreactant is not usually added to the mixture of sandsimultaneously with the resin, although it can be, if the mixing actionis sufficiently vigorous. Typically, the mixture of sand and resinshould be mulled for at least about two minutes before the coreactant isadded, and I have found that mulling the mixture for about five minutesyields a very satisfactory product. After the coreactant has been added,the mixture should be mulled for another short period, but care shouldbe taken not to heat up the mixture by excessive mulling, because suchheating could accelerate polymerization of the resin.

FIG. 2 shows a block 19 formed by combining granular material colored bythree different paint colors, but instead of having the colors separatedfrom each other in flat layers, as in FIG. 1, the colored materials21-23 are intermingled with each other. The intermingling is donecarefully so that each small region is visibly distinct and hasrelatively sharp boundaries. This is achieved by forming, at the sametime, three different slurries of granular material colored by threedifferent paint colors and mixing all three together while all are stillin the liquid state. The mixing must not stir the three colors sointimately together that the block 19 will appear to have just onecolor, which is the additive result of the three color components. Thecolors should be kept separate so that the visual effect is that theblock 19 somewhat resembles marble, with a main region 21 that appearswhite in this figure and other regions 22 and 23 colored by twodifferent paints. It is not necessary to mix three colors together;attractive results can also be achieved by mixing two or more differentcolored regions, as long as they remain visibly separate. As in FIG. 1,the physical characteristics may be kept identical so that, when theblock 19 is carved, there is no difference in the way the three regionsreact to carving tools.

Due to the fact that care must be exercised in mixing the materials toproduce the marbleized effect, it is necessary that none of the slurriesharden too soon. Delta produces a resin, identified as 18-94 in their18-00 series, that an be worked, or stirred, for 120 minutes, and usingthat resin allows the three slurries to be relatively gently stirredtogether to achieve good intermingling while retaining sharp boundaries.The Delta resin 18-94 has a limited amount of a catalytic curing, ordrying agent, such as Delta's 1718-X catalyst in it to allow a longstirring, or working, time. The same result can be achieved by using aresin without any catalyst in it and adding the catalyst while themixing is going on.

The difference between the block 11 in FIG. 1 and the block 19 in FIG. 2is that the block 11 can be formed in a small mold, or recess, havingthe size of the block to be sold to customers, or it can be formed as alarge slab and cut into small blocks of the size to be sold. Themarbleizing effect in FIG. 2 does not reach to the edges of the mold inwhich the marbleized material is formed. Thus, it must be formed as alarger piece than is to be sold, and it must be cut into a smallerpiece, or pieces, not including the edge portions.

After the coreactant has been put into the slurry, and any necessaryworking done, the slurry must be poured into a mold or molds, unless itis to harden in the container in which it is formed. Then, the mold orcontainer, or the whole table on which the mold (or molds) or containeris located is vibrated for about one to 30 seconds to settle the slurryand work out any gas entrapped therein. If the slurry is in a mold, itis desirable to put in more than enough to fill the mold and then tovibrate it until the top of the slurry is level with the top of themold. Then a cap is placed on the mold to cover the mold and the slurry,and the whole thing is vibrated for one to about 60 seconds to achievethe desired compaction. In order to get the material out of a mold, arelease agent is used.

FIG. 3 shows a partially sculpted block 24 of another type of material.As in the block 11 in FIG. 1 and the block 19 in FIG. 2, the block 24 ismade of granular material held together by a resin binder. In FIG. 3,the main material 26 of which the block 24 is formed is made of granularmaterial coated with paint of one color, and chips of preformed material27 and 28 are dispersed throughout the materials 26. The chips are madein the same way as the layer 12 in FIG. 1, except for being coloreddifferently. Once two layers are formed and hardened, they are broken upinto small chips 27 and 28, which are stirred into the slurry of whichthe main material 26 is formed. The material 26 solidifies around thechips, forming a monolithic block. Since the chips have the samephysical constitution as the main material, the entire block 24 respondsto carving as if there were only one material. It can be seen in thedrawing that the smooth, sculpted surfaces of the abstract figure 29pass through the chips 27 and 28 as if they were the same as thematerial 26, but the chips add visual interest to the sculpture.

FIG. 4 shows another partially carved figure. In this case, a block 31of granular material held together by a resin binder encloses adifferent type of preformed figure which, in this instance, is made ofplastic, although it may be a figure made of harder sculpting stone,glass, wood and other man-made and natural materials that cannot becarved or, at least cannot be carved as easily as the block 31. Thepurpose of forming the block 31 this way is for it to serve as anintroductory device that will interest small children in sculpting. Inthis instance, the block is softer than in the previous embodiments andcan even be so soft that it an be carved by brushing away the granularmaterial with a stiff-bristled brush. The brush, or even an ordinary,hard carving tool, would not affect the dinosaur, and the child wouldbecome interested in seeing the appearance of a recognizable shape bythus sculpting the block 31. It is to be understood that, prior to thechild's efforts, the block 31 was a parallelepiped, like the block 11 inFIG. 1, and the dinosaur 32 was completely hidden within it.

FIG. 5 shows a randomly shaped piece of sculpting stone 33 similar tothe blocks 11, 19, and 24, except that the piece 33 has geometricalpieces 34-36 in it. These represent, respectively, segments ofmulti-layered, multi-colored cylinders 34 of sculpting stone; crystalsor diamonds or gemstones 35; and thin discs 36. In addition, the stone33 has flakes, or pieces 37, of glittering material throughout it and onits surface to make it more interesting, and the whole stone 33 may besuffused with a chemical that emits a pleasant fragrance. The chemicaland any of the additive materials 34-37 can be incorporated in any ofthe sculpting stones show in FIG. 1-4; there is no limit in thisinvention to such modifications.

What is claimed is:
 1. A dry, three-dimensional, sculptable solidcomprising:(a) a quantity of granular material comprising grainsindividually coated with paint; and (b) water-resistant binder bindingthe grains of the granular material together into a solid, dry, carvableblock having a hardness between about 0.25 and about 4.0 on the Moh'sscale.
 2. The dry, three-dimensional, sculptable solid of claim 1 inwhich the coating of paint on the grains comprises alkyd paint.
 3. Thedry, three-dimensional, sculptable solid of claim 1 in which the bindercomprises an oil-based alkyd resin.
 4. The dry, three-dimensional,sculptable solid of claim 3 in which the grains of the granular materialin one part of the solid have a coating of a first paint having a firstcolor, and the grains of the granular material of a visibly separatesecond part of the sculptable solid have a coating of a paint of asecond color.
 5. The dry, three-dimensional, sculptable solid of claim 4in which substantially all of the first part is one one side of a planethrough the solid, and substantially all of the second part is on theother side of the plane.
 6. The dry, three-dimensional, sculptable solidof claim 4 in which both parts are of substantially equal hardness. 7.The dry, three-dimensional, sculptable solid of claim 4 in which thesecond part is divided into pieces smaller than the first part but stillvisibly distinct from the first part and dispersed within the firstpart.
 8. The dry, three-dimensional, sculptable material of claim 7 inwhich the pieces into which the second part is divided are of randomshapes.
 9. The dry, three-dimensional, sculptable solid of claim 7 inwhich the pieces into which the second part is divided are geometricalshapes.
 10. The dry, three-dimensional, sculptable solid of claim 9 inwhich at least some of the pieces are further divided into visiblyseparate regions, the paint on the grains of the granular material ineach of the regions being different in color from the paint on thegrains of the granular material in the next-adjacent region.
 11. Thedry, three-dimensional, sculptable solid of claim 1 further comprisingparticles of shiny, light-reflective material.
 12. The dry,three-dimensional, sculptable solid of claim 1 in which the granularmaterial is sand having a fineness such that the sand is capable ofpassing through a sieve of A.S.T.M. mesh number not substantiallynumerically smaller than
 40. 13. The dry, three-dimensional, sculptablesolid of claim 12 in which the sand has a fineness such that the sand iscapable of passing through a sieve with a mesh number between about 40and
 180. 14. The dry, three-dimensional, sculptable solid of claim 1further comprising at least one solid item therein that is having ahardness substantially greater than that of the sculptable mold.
 15. Thedry, three-dimensional, sculptable solid of claim 14 in which the soliditem is made of material from the class consisting of: plastic, glass,wood, metal, and stone.
 16. The dry, three-dimensional, sculptable solidof claim 14 in which the solid item is made of granular material havinga higher percentage of resin than the sculptable solid.
 17. The dry,three-dimensional, sculptable solid of claim 1 having a hardness betweenabout 0.25 Mohs and about 2.0 Mohs.
 18. A dry, three-dimensional,sculptable solid comprising:(a) granular material; (b) a coating ofpaint at least substantially encasing each grain of the granularmaterial; and (c) a water-resistant binder binding the paint coating onthe grains of the granular material together to form a dry solid,carvable block having a hardness between about 0.25 and about 4.0 on theMoh's scale.
 19. The dry, three-dimensional, sculptable solid of claim18 in which the color of the paint on each grain of the granularmaterial in one visibly indentifiable part of the block is differentfrom the color on each grain of the granular material in a secondvisibly identifiable part of the block.
 20. The dry, three-dimensional,sculptable solid of claim 19 in which the color of the paint on eachgrain of the granular material in the one visibly identifiable part ofthe block is the same as the color of the paint of all of the grains ofthe granular material in the same one visibly identifiable part of theblock.